The present invention relates generally to hand held power tools.
Hand held power tools are well known and widely utilized. In order to chisel with a tool, for example a flat chisel in different rotary positions. It is known to provide a hammer drill with a tool holder which can be adjusted in a rotary direction to different positions.
The tool holders as a rule have a base body which is fixed in an axial direction and in which a grooved shaft is displacable in an axial direction within a range which is limited by locking bodies. The base body is fixed in a rotary direction through individual locking balls which engage radially inwardly in grooves provided on the periphery of the base body and radially outwardly in recesses provided in an adjoining non-rotary component. In the locked condition, the locking balls are fixed radially outwardly by a locking sleeve which is guidable via an actuating sleeve to a position which radially releases the locking balls.
Accordingly, it is an object of present invention to provide a hand power tool which is a further improvement of the hand power tools of this type. More particularly, it is an object of present invention to provide a hand power tool, in particular a hammer drill with a tool holder which is strikingly drivable and has a base body, which is form-lockingly connectable at least with a locking body and is fixable through the base body in a rotary direction in at least two positions.
In keeping with these objects and with others which will become apparent hereinafter, it is proposed that the locking body is formed by a ring-shaped component. With a ring, which can be composed of a single part or many parts, it is possible in a structurally simple and cost-favorable manner to provide a large transmission surface, a small surface pressure, a small wear, and a high service life. Furthermore, a ring-shaped locking body can be mounted fast and simple and dismounted in the same way.
The locking bodies can be formed of one piece with another, preferably available component, for example in actuating sleeve, so that an additional component can be dispensed with.
In accordance with another embodiment of the present invention, it is proposed that the locking body is formed as a separate arresting ring. It can therefore provide a short structural length, and in particular with a separate arresting ring, a radial distance can be bridged, and a radially outer diameter over the periphery with an especially large transmission surface can be obtained.
The arresting ring preferably can have a set of teeth with a cross-section having at least partially trapeze-shaped recesses and/or trapeze-shaped teeth, for transmitting high torques.
The inventive solution can be used for different hand power tools with different tool holders. Due to the provision of a large transmission surface in a rotary direction, the inventive solution is suitable in particular for a tool holder with an axially displaceable base body for providing an idling or a drive connection, in which the transmission surface additionally is loaded by an axial movement and thereby with corresponding friction.
In order to guide the base body in its axial movement on a maximum possible diameter, over which a large transmission surface is obtained, the arresting ring can be mounted on the base body of the tool holder in an axial direction and guided in an axial direction in a set of teeth of a non rotatable component.
In accordance with another embodiment of the present invention, it is proposed that the base body of the tool holder is supported in the rotary direction over at least a set of teeth on an actuating sleeve, which preferably is also supported with at least one set of teeth in a housing part. Additional components, structural space, weight, mounting expenses and cost can be saved. Further, the set of teeth between the actuating sleeve and the housing part can provide an adjustment path which is independent from the axial position of an axially displaceable base body for locking and unlocking the base body in the rotary direction.
In order to provide simple turning of the actuating sleeve in the unlocked position of the base body, it is advantageous when the actuating sleeve is displaceable in an axial direction, and the connection between the first set of teeth of the actuating sleeve and the housing part is releasable by an axial actuating path before a connection between the second set of teeth of the actuating sleeve and the locking body. Furthermore, a short adjustment path for locking and unlocking can be obtained with a short set of teeth in the axial direction in the housing part.
The set of teeth in the housing part is arranged preferably radially inwardly and/or outwardly of a material ring. With the material ring a mechanical reinforcement of the set of teeth is provided. In particular, advantageously the region of the material ring in the case of the housing part formed as a gas part, can be used advantageously as a casting location during the manufacture.
The set of teeth in the housing part formed as a cast part has in its cross-section preferably at least partially round recesses and/or round teeth. They are advantageously molded and can be formed as highly loadable. Stress peaks can be avoided by great radii.
With the inventive solution a large transmission surface for the actuating sleeve is provided in a cost favorable manner, the actuating sleeve and/or the locking body can be advantageously formed as synthetic plastic parts and therefore produced in a specially cost favorable and simple manner.
For protecting the transmission surfaces from dust and dirt, and reducing or avoiding wear due to dirtying, it is proposed that a space which surrounds the locking body is structurally simply sealed outwardly by at least one sealing element. The sealing element in a structurally simple and cost favorable manner can be arranged between the actuating sleeve and an adjoining component.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.